mechanical and physical parameters
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Cílem práce bylo popsat novou metodu pro hodnocení mechanické odolnosti tablet. Klasická lékopisná metoda měření pevnosti tablet zjišťuje sílu, při které dojde k prasknutí tablety. Zjištěná síla se vyjadřuje v N. Nová metoda měření pevnosti tablet vychází ze záznamu síla – dráha, zjištěného při drtícím procesu. Při této metodě se zjišťuje nejen drtící síla DS v N a z ní přepočtená radiální pevnost RP v MPa, ale i další parametry jako dráha drcení d v mm, rychlostní konstanta drtícího procesu k v kNmm-1, deformační energie DE v mJ a objemová deformační energiev MJ.m-3. Nové parametry jsou prezentovány na tabletách z mikrokrystalické celulózy Avicelu PH 102.
The paper aims to describe a new method for the evaluation of mechanical strength of tablets. The classic pharmacopoeial method of measurement of strength of tablets examines the strength at which the tablet breaks, the found strength being expressed in N. The proposed method of measurement of tablet strength is based on the strength-course record, determined during the process of crushing. This method determines not only the crushing force (DS) in N and the radial strength (RP) in MPa calculated from it, but also other parameters, such as the course of crushing d in mm, the rate constant of crushing process in kNmm-1, the deformation energy DE in mJ, and the volume deformation energy ODE in MJ.m-3. The new parameters are illustrated on tablets from the microcrystalline cellulose Avicel PH 102.
Článek se zabývá popisem rozdílů mezi konvenční a vysokofrekvenční ventilací z hlediska rozdílných fyzikálních principů proudění plynů.Uvádí vliv plicní mechaniky na intrapulmonální poměry při konvenční i vysokofrekvenční ventilaci. Detailně jsou sledovány rozdíly mezi jednotlivými parametry charakterizujícími ventilační režim s diskusí o jejich významu pro efektivní a bezpečné řízení konvenční a vysokofrekvenční ventilace.
The article deals with differences between the conventional mechanical ventilation and a high-frequency ventilation. First, the different physical principles of gas flow are described. Then, effects of the mechanical properties of the respiratory system upon intrapulmonary conditions are studied in both ventilatory regimens. Differences between the parameters characterising each ventilatory regimen are explained. Finally, the importance of the ventilatory parameters for a safe and efficient application of both conventional and high-frequency ventilations is examined.
Understanding the mechanics of the respiratory system is crucial for optimizing ventilator settings and ensuring patient safety. While simple models of the respiratory system typically consider only flow resistance and lung compliance, lung tissue resistance is usually neglected. This study investigated the effect of lung tissue viscoelasticity on delivered mechanical power in a physical model of the respiratory system and the possibility of distinguishing tissue resistance from airway resistance using proximal pressure measured at the airway opening. Three different configurations of a passive physical model of the respiratory system representing different mechanical properties (Tissue resistance model, Airway resistance model, and No-resistance model) were tested. The same volume-controlled ventilation and parameters were set for each configuration, with only the inspiratory flow rates being adjusted. Pressure and flow were measured with a Datex-Ohmeda S/5 vital signs monitor (Datex-Ohmeda, Madison, WI, USA). Tissue resistance was intentionally tuned so that peak pressures and delivered mechanical energy measured at airway opening were similar in Tissue and Airway Resistance models. However, measurements inside the artificial lung revealed significant differences, with Tissue resistance model yielding up to 20% higher values for delivered mechanical energy. The results indicate the need to revise current methods of calculating mechanical power delivery, which do not distinguish between tissue resistance and airway flow resistance, making it difficult to evaluate and interpret the significance of mechanical power delivery in terms of lung ventilation protectivity.
- MeSH
- dýchání fyziologie MeSH
- lidé MeSH
- mechanický stres MeSH
- spotřeba kyslíku MeSH
- Check Tag
- lidé MeSH
... Anatomy, 429 Patient History, 434 Observation, 434 -- Common Hand and Finger Deformities, 436 Other Physical ... ... 981 Stance Phase, 9S2 Swing Phase, 982 Double-Leg Stance, 984 Single-Leg Stance, 984 -- Normal Parameters ... ... and Patient History, 994 Observation, 994 Examination, 996 -- Locomotion Scores, 997 Compensatory Mechanisms ... ... Examination for Cold (Hypothermic) Disorders, 1087 Laboratory Tests, 1087 Diagnostic Imaging, 1088 Physical ...
6th edition x, 1173 s. : il., tab. ; 29 cm
- MeSH
- fyzikální vyšetření MeSH
- nemoci kloubů diagnóza MeSH
- nemoci kostí diagnóza MeSH
- ortopedické výkony metody MeSH
- Publikační typ
- monografie MeSH
- příručky MeSH
- Konspekt
- Ortopedie. Chirurgie. Oftalmologie
- NLK Obory
- ortopedie
- revmatologie
- NLK Publikační typ
- učebnice vysokých škol
The purpose of this review is to evaluate new concepts in mechanical ventilation in trauma. We begin with the keystone of physiology prior to embarking on a discussion of several new modes of mechanical ventilation. We will discuss the use of noninvasive ventilation as a mode to prevent intubation and then go on to airway pressure release ventilation, high-frequency oscillatory ventilation, and computer-based, closed loop ventilation. RECENT FINDINGS: The importance of preventing further injury in mechanical ventilation lies at the heart of the introduction of several new strategies of mechanical ventilation. New modes of ventilation have been developed to provide lung recruitment and alveolar stabilization at the lowest possible pressure. SUMMARY: The old modes of continuous positive airway pressure and bilevel positive airway pressure have been actively introduced in clinical practice in the case of trauma patients. Used with proper pain management protocols, there has been a decrease in the incidence of intubation in blunt thoracic trauma. Airway pressure release ventilation has been gaining a role in the management of thoracic injury and may lead to less incidence of physiologic trauma to mechanically ventilated patients. High-frequency oscillatory ventilation has been shown to be effective in patient care by its ability to open and recruit the lung in trauma patients and in those with acute respiratory distress syndrome but it may not have a role in patients with inhalational injury. Closed loop ventilation is a technology that may better control major pulmonary parameters and lead to more rapid titration from the ventilator to spontaneous breathing.
- MeSH
- fyziologie dýchací soustavy MeSH
- lidé MeSH
- mechanické ventilátory MeSH
- rány a poranění patofyziologie terapie MeSH
- umělé dýchání MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
... The physiology of physical agents -- Physical agents in clinical practice -- Inflammation and tissue ... ... Contents -- Part I Introduction to Physical Agents 1 -- 1 The Physiology of Physical Agents 1 -- How ... ... , 2 Categories of Physical Agents, 2 Effects of Physical Agents, 3 -- General Contraindications and Precautions ... ... for Physical Agent Use, 9 -- Evaluation and Planning for the Use of Physical Agents, 10 -- Documentation ... ... The Role of Physical Agents in Rehabilitation, 17 Practitioners Using Physical Agents, 17 Evidence-Based ...
4th ed. xvii, 437 s. : il. ; 28 cm
... ^x\' 62 -- 4.5.2 Short-Lived RF Pulses 63 -- 4.5.3 Long-Lived RF Pulses 64 -- 5 The Quantum Mechanical ... ... Demodulation 104 -- 7.3.4 Dependent Channels and Independent Coils 107 -- 7.4 Dependence on System Parameters ... ... on Read Direction Parameters 336 -- 15.2.3 SNR Dependence on Phase Encoding Parameters 340 -- 15.2.4 ... ... to Coherent Steady-State 476 -- 18.2.3 Utility of SSC Imaging 479 -- 18.3 SSFP Signal Formation Mechanisms ... ... Angle Pulse 481 -- 18.3.2 Multi-Pulse Experiments and Echoes 484 -- 18.4 Understanding Spoiling Mechanisms ...
Second edition xxxii, 944 stran : ilustrace ; 29 cm
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- radiologie, nukleární medicína a zobrazovací metody
- NLK Publikační typ
- kolektivní monografie
